Effective, ongoing communication between patients and providers is an important component of diabetes and chronic illness care. Patients with diabetes and multiple chronic conditions are particularly dependent on effective communication with a primary physician over time to motivate and troubleshoot care. Unfortunately, our current health care system's focus on the clinic visit does not meet the needs of these patients. Chronic disease care using patient Web portals offers an opportunity to shift the focus in health care away from the office and toward patients'daily lives at home. We propose to evaluate the association between the quality of chronic illness care among patients with diabetes and the use of a Web-based, interactive electronic medical record shared between patients and health care providers. To achieve this goal, we will study a large and secure patient Web portal in the natural setting of care at Group Health Cooperative (Group Health). Group Health's Web portal, MyGroupHealth, allows enrollees to: 1) exchange electronic messages with their entire health care team including physicians;2) access their electronic medical records in real time;3) obtain after-visit summaries with embedded hyperlinks to the Healthwise knowledge base;4) obtain refills on medications with shipping directly to patients'homes;5) schedule office appointments with providers;and 6) access health education information that is tailored and linked to their specific health conditions. The study will focus on the primary care of patients with diabetes and one or more other chronic conditions. In retrospective analyses, we will first evaluate predictors of portal adoption and whether use of the electronic portal is associated with better clinical quality of care. In a cross-sectional survey of a subsample of this cohort, we will then evaluate whether portal use is associated with better primary care relationships, patient activation and patient's assessment of chronic illness care. Through content analysis, we will evaluate whether the qualities of patient-provider secure messages and patients'after-visit summaries are associated with better chronic illness care. Finally, through qualitative interviews of patients and their primary care providers, we will seek to understand where the Web portal meets and fails to meet patients'needs. Results of this study will help inform the development, evaluation and dissemination of patient Web portals designed to support the care of patients with diabetes and multiple co-morbidities.